THE VEGETABLE GARDEN 



211 



FIG. 112. Lima Bean 



GERMINATION OF SEEDS 



Parts of seeds. A seed consists of the embryo (a minia- 

 ture plant commonly called the germ) and its coverings. 



The seed coat of the bean is called 

 the testa. The little opening in the 

 testa, which may be found by squeez- 

 ing a seed that has been soaked, is 

 known as the micropyle. The place 

 where the seed was attached to the 

 pod is called the hilum (see Fig. 112). 

 The embryo of the bean 

 has three parts : the small 

 stem, or hypocotyl ; the 

 seed leaves, or cotyledons ; 

 and the bud, or plumule. 

 Food material for the sup- 

 port of the 

 young plant 



is stored in the cotyledons (see Fig. 113). 

 After cracking the shell-like seed coat 

 of the castor bean we find that the part 

 within is covered with a delicate mem- 

 brane, the inner seed coat. The food 

 material within this coat contains the 

 very thin cotyledons, that absorb the 

 food stored around them. When the food material is 

 stored on the outside of the cotyledons, as in the castor 

 bean, it is known as endosperm (see Fig. 115). 



Plumule 

 Hypocotyl 



Cotyledon 



FIG. 113. Lima Bean opened 

 Lengthwise 



FIG. 114. A Castor 

 Bean 



